Found some horsetail in the garden! I had not noticed it growing here last year, or in previous years, (we were growing willows here last year and didn't do any weeding around them). It's neat to find something wild that some people cultivate!
Horsetail is a medicinal plant. It contains ephedrine. It's used for lowering blood pressure, can be good for the skin, and has many uses related to the kidney and bladder. I didn't know much about it but there's plenty to read about it. I pulled out some of it but left a few plants to grow.